This invention relates to a circuit for detecting an operating center of an actuator of an optical head for optically recording and reproducing data to and from an optical disk, and to an optical disk apparatus with the actuator operating center detecting circuit.
When the optical disk apparatus reads out the data recorded on the optical disk, the pick-up head is subjected to a motion, such as track jump and access control. Even under the motion, the reproducing laser beam emitted from an optical pick-up head must exactly be landed on a desired track of the optical disk. In such tracking control, however, there is limited a control range in which an actuator to drive the objective lens system is stably moved. Therefore, if the direction and the motion amount of the optical head and the objective lend system are improper, an abberation is possibly caused in the optical system. The abberation caused creates an error in the read out signal. To avoid this, it is necessary to accurately detect the operating center position of the actuator. The tracking must be performed within a stable operating range of the actuator on the basis of the detected operating center position of the actuator.